Transmission line flashover detector



Jan. 27, 1948. A. L. KINYON ETAL 2,434,933

TRANSMISSION LINE FLASHOVER DETECTOR Filed March 26, 1945 F l G- 3 Allan L. Kinyan INVENTORS.

William E Scarborough BY Won- 7.

Patented Jan. 27, 1948 TRANSMISSION LINE msnovnn ns'raoron Allen L. Kinyon, Vancouver, Wash., and William E. Scarborough, Portland, reg., assignors to the United States of America, as represented by the Secretary of the Interior Application March 26, 1945, Serial No. 585,000

3 Claims. (Cl. 177-311) (Granted under the act of March 3, 1883, an amended April 30, 1928; 370 0. G. 757)" The invention described herein may be manufactured and used by or for the Government of the United States for governmental purposes without the payment to us of any royalty thereon in accordance with the provisions of the act of April 30, 1923 (Ch. 460, 45 Stat. L. 467) Our invention relates to a means for the detection of lightning fiashovers from electrical transmission lines to the ground through one of a plurality of transmission line towers, and particularly to a means which may be mounted on a tower leg at a point readily accessible from the ground. With the aid of our invention a lineman may quickly determine through which tower, or towers, lightning fiashovers have occurred since a previous inspection; then climb each tower where a fiashover is detected to inspect the transmission line insulators and determine whether or not any have been damaged by the lightning flashover; thus facilitating prompt replacement or repairs.

In the accompanying drawings:

Figure 1 is an elevation of one embodiment of our invention.

Figure 2 is a perspective detail illustrating a preferred means for mounting our device on a tower leg.

Figure 3 is a view of a transmission line with a tower equipped with one of our devices.

In these drawings, l0 designates an endless wire loop having a bifurcation H for the purpose of attaching the loop ill to a transmission line support. The loop I0 includes a multi-turn helix l2 and within said helix I2 is removably mounted a magnetic link l3 preferably made of cobalt steel in an insulating case having suitable means for supporting the link l3 within the coil I: as by a plurality of cars or extrusions H.

In Figure 2 a means for mounting our loop ill on a tower leg comprises a suitable headed bolt 23, a nut 24, a washer and a spacing washer 26, the headed bolt 23 having been inserted through a bolt hole in the tower leg 20.

In Figure 3 there is diagrammatically shown a conventional transmission line supporting tower I provided with three ceramic insulator strings 42 each supporting a transmission line conductor 48. To a leg of the tower ll one of the devices is bolted with a portion of the loop Ill protruding in the direction of a companion tower leg.

When lightning strikes one of the transmission lines 43 it may follow the line to one of several transmission line towers ll, flash over a supporting insulator string 42 and follow the metallic members of the tower 4i and the tower supporting legs 20 to the ground.

A single device is attached to one leg 20 of each tower 4 I, it being assumed that the lightning will divide among the plurality of tower legs. The passage of a flash of lightning through a leg 20 will induce a current in our loop l0 and the coils of our helix i2, and this current surge will permanently magnetize the link l3. Thereafter a lineman may quickly determine whether or not a flashover has passed through the-supporting tower 4| by removing the link l3 and holding it near a compass or by employing any other means for indicating that the link i3 has been magnetized. Whenever he finds a magnetized link he makes a detailed inspection to determine what damage may have occurred to the insulators, tower or conductors. Such damage may then be repaired with a minimum loss of time in the restoration of service or the prevention of possible future outages On important high revenue transmission lines. He replaces the link with one which has been de-magnetized.

In one embodiment of our invention our loop i0 is made of number nine iron wire approximately seven inches by thirteen inches, while our helix i2 has seven turns of amean diameter of one-half inch. The inductance of the helix is approximately 0.15 microhenry, the impedance at cycles approximately 0.14 ohm, while at 25 cycles it is approximately 0.06 ohm, within the tolerance of construction precision of the loop now in use. The inductance has shown no peaking effect at frequencies up to live megacycles, which is generally accepted to be equivalent to the rate of rise of the more severe lighting surges.

It should be understood that the present disclosure is for the purpose of illustration only. and that'the invention includes all modifications and equivalents which fall within the spirit and scope of the appended claims, in which it is our intention to claim all novelty inherent in our invention as broadly as possible in view of the prior art.

What we claim is:

1. A supporting structure for a transmission 3 line iii-combination with a lightning flashover detection device comprising a closed loop including a multi-turn helix of material of fair electrical conductivity, and a magnetizable link replacably supported in said helix.

2. A flashover detector comprising a magnetizable link, a holder comprising a closed loop including an integral helix having a degree oi conductivity such that induced lightning currents will magnetize a permanently magnetizable link within said helix but will not magnetize said link by power currents.

3. A flashover detector adapted to be mounted in operative position on an electrical transmission line support comprising a closed loop with a helical element formed therein and a removable magnetizable element adapted to be mounted within the helical element and in be magnetized when current is induced in the loop by surges of lightning through said support to enable an inspector to ascertain by means oi the magnetizable element whether or not a lightning flashover might have aii'ected some parts of a transmission line in that vicinity. 1

ALLEN L. KINYON.

E. SCARBOROUGH.

REFERENCES CITED The following references are of record in the tile oi this patent:

UNITED STATES PATENTS 16 Number Name Date 1,881,560 'I'atz Aug. 21, 1928 1,942,384 Foust Jan. 2, 1934 2,236,277 Sturtevant Mar. 25, 1941 

